Synthesis of L-Lactide from Butyl Lactate： Selection of Catalyst

The process of production of lactide from butyl lactate was investigated. The process consists of two stages： oligomerisation of butyl lactatean and depolymerisation of oligomers. The type catalysts of the series of Lewis acid were tested. It was found that SnCI4 is the most efficient catalyst for both stages.

LDH、NT-proBNP、ALB水平对不完全性川崎病的早期诊断价值

目的:探讨乳酸脱氢酶(LDH)、N末端脑钠肽前体(NT-proBNP)、白蛋白(ALB)水平对不完全性川崎病(IKD)的早期诊断价值。方法:选取巴彦淖尔市医院2020年1月—2023年1月收治的80例IKD患儿作为IKD组,选取本院同期收治的80例典型川崎病(KD)患儿作为KD组。所有患儿入院后检测LDH、NT-proBNP、ALB水平,对比IKD组与KD组一般情况和LDH、NT-proBNP、ALB水平。通过受试者操作特征(ROC)曲线分析LDH、NT-proBNP、ALB水平对IKD的早期诊断价值。同时将80例IKD患儿依照冠脉损伤情况分为两个亚组,即无损伤组(n=30)和损伤组(n=50),对比两组LDH、NT-proBNP、ALB水平。结果:IKD组和KD组性别、年龄及高热、多形性皮疹、口腔黏膜变化占比对比,差异均无统计学意义(P>0.05);IKD组发热时间长于KD组,指端改变、结膜充血、颈部淋巴结肿大占比低于KD组,差异均有统计学意义(P<0.05);IKD组LDH、NT-proBNP、ALB水平均明显高于KD组,差异均有统计学意义(P<0.05);LDH、NT-proBNP、ALB三者联合对IKD的诊断效能优于单一检测;损伤组LDH、NT-proBNP、ALB水平均明显高于无损伤组,差异均有统计学意义(P<0.05)。结论:LDH、NT-proBNP、ALB水平对IKD的早期诊断价值较高,且临床可考虑通过LDH、NT-proBNP、ALB三者联合来诊断IKD。

臭氧化法制备N-Boc-(甲氨基)乙醛

以N-甲基烯丙胺和二碳酸二叔丁酯为原料,在乙醇中缩合得到N-Boc-甲基烯丙胺,再以乙酸乙酯为溶剂经臭氧臭氧化,用NaHSO_(3)还原分解,经萃取、蒸馏,制备N-Boc-(甲氨基)乙醛。采用L16(45)正交实验确定了最优臭氧化温度为5~10℃、反应时间为3 h、臭氧流量为0.04 m^(3)/h,粗产物用乙醚萃取,获得目标产物收率78.7%,纯度99.2%(HPLC),并用IR、^(1)H NMR、^(13)C NMR和MS表征了产物的结构。

Developmental Toxicity in Mice Following Paternal Exposure to Di-N-Butyl-Phthalate (DBP)

Objective The aim of the present study was to investigate the effects of paternal Di‐N‐butyl‐phthalate （DBP） exposure pre‐ and postnatally on F1 generation offspring,and prenatally on F2 generation offspring.Methods Male mice were exposed to either 500 mg/kg or 2 000 mg/kg of DBP for 8 weeks,and mated with non‐exposed females.Three‐quarters of the females were sacrificed a day prior to parturition,and examined for the number of living and dead implantations,and incidence of gross malformations.Pups from the remaining females were assessed for developmental markers,growth parameters,as well as sperm quantity and quality.Results There were no changes in the fertility of parents and in intrauterine development of the offspring.Pups of DBP‐exposed males demonstrated growth‐retardation.Following paternal exposure to 500 mg/kg bw of DBP,there were almost twice the number of males than females born in the F1 generation.F1 generation females had a 2.5‐day delay in vaginal opening.Paternal exposure to 2 000 mg/kg bw of DBP increased the incidence of sperm head malformations in F1 generation males;however,there were no changes in the fertility and viability of foetuses in the F2 generation.Conclusion Paternal DBP exposure may disturb the sex ratio of the offspring,delay female sexual maturation,and deteriorate the sperm quality of F1 generation males.

Heteropolyacids Catalysis in Synthesizing Butylacrylate

The catalytic activities of some heteropolyacids(HPAs) in synthesizing butyl acrylate are reported. It has been demonstrated that 12 tungstophosphoric acid is the most effective catalyst among more than 20 HPA(salts). Various factors concerned in this reaction have been investigated. The optimum conditions have been found, that is, the molar ratio of alcohol to acid is 1.2∶1.0 , the catalyst concentration 1%(mass fraction), the reaction time 2 h, the temperature 98—124 ℃ and a certain amount of polymerization inhibitor exists.

CO_2 capture from binary mixture via forming hydrate with the help of tetra-n-butyl ammonium bromide

Hydrate formation rate and separation effect on the capture of CO2 from binary mixture via forming hydrate with 5 wt% tetra-n-butyl ammonium bromide （TBAB） solution were studied. The results showed that the induction time was 5 min, and the hydrate formation process finished in 1 h at 4.5 ℃ and 4.01 MPa. The hydrate formation rate constant reached the maximum of 1.84× 10^-7 molZ/（s.J） with the feed pressure of 7.30 MPa. The CO2 recovery was about 45 % in the feed pressure range from 4.30 to 7.30 MPa. Under the feed pressure of 4.30 MPa, the maximum separation factor and CO2 concentration in hydrate phase were 7.3 and 38.2 mol%, respectively. The results demonstrated that TBAB accelerated hydrate formation and enriched CO2 in hydrate phase under the gentle condition.

Esterification of levulinic acid to n-butyl levulinate over heteropolyacid supported on acid-treated clay

Levulinic acid has been identified as a promising green, biomass-derived platform chemical. n-Butyl levulinate is used as an important intermediate having diverse applications. The present work focuses on the synthesis of n-butyl levulinate by esterification of levulinic acid with n-butanol using heteropolyacid （HPA） supported on acid-treated clay montmorillonite （K10）. 20% （w/w） dodecatungestophosphoric acid （DTPA） supported on K10 was found to be the most efficient catalyst with 97% levulinic acid conversion and 100% selectivity towards n-butyl levulinate. Effects of various process parameters were studied to examine the efficacy of 20% （w/w） DTPA/K10 for optimization of the activity.

Effects of di-n-butyl phthalate on male rat reproduction following pubertal exposure

Di-n-butyl phthalate （DBP） is an endocrine-disrupting chemical that has the potential to affect male reproduction. However, the reproductive effects of low-dose DBP are still not well known, especially at the molecular level. In the present study, pubertal male Sprague-Dawley rats were orally administered DBP at a wide range of doses （0.1, 1.0, 10, 100 and 500 mg kg^-1 day^-1） for 30 days. The selected end points included reproductive organ weights, testicular histopathology and serum hormonal levels. Additionally, proteomic analysis was performed to identify proteins that are differentially expressed as a result of exposure to DBP at low doses （0.1, 1.0 and 10 mg kg^-1 day^-1）. Toxic effects were observed in the high-dose groups, including anomalous development of testes and epididymides, severe atrophy of seminiferous tubules, loss of spermatogenesis and abnormal levels of serum hormones. Treatment with low doses of DBP seemed to exert a ＇stimulative effect＇ on the serum hormones. Proteomics analysis of rat testes showed 20 differentially expressed proteins. Among these proteins, alterations in the expression of HnRNPA2/B1, vimentin and superoxide dismutase 1 （SOD1） were further confirmed by Western blot and immunohistochemistry. Taken together, we conclude that high doses of DBP led to testicular toxicity, and low doses of DBP led to changes in the expression of proteins involved in spermatogenesis as well as changes in the number and function of Sertoli and Leydig cells, although no obvious morphological changes appeared. The identification of these differentially expressed proteins provides important information about the mechanisms underlying the effects of DBP on male rat reproduction.

Efficient one-pot synthesis of n-butyl levulinate from carbohydrates catalyzed by Fe_2(SO_4)_3

Butyl levulinate（BL） is a promising new candidate as diesel fuel and fuel additive. In this study, an efficient process for a one-pot synthesis of BL from biomass-derived carbohydrates in butanol medium with the catalysis of metal sulfates was developed. The catalytic activity of a series of metal sulfates for the synthesis of BL from fructose was investigated. Among various metal sulfates, ferric sulfate Fe（SO）was found to be the most efficient catalyst, which gave a remarkably high BL yield of 62.8 mol% under the conditions of 463 K, 3 h, a catalyst dosage of 5.0 g/L, and fructose concentration of 25 g/L. Different carbohydrates including glucose, cellulose, inulin and sucrose were also used for one-pot synthesis of BL with the catalysis of Fe（SO）, showing the yields of 39.6, 30.5, 56.6 and 50.1 mol%, respectively. In addition,the recycling and reuse of Fe（SO）was studied by characterizing them using powder X-ray diffraction（XRD）, scanning electron microscope（SEM）, X-ray photoelectron spectroscopy（XPS）. A plausible reaction pathway for the one-pot synthesis of BL from fructose was proposed. This study provides a facile and feasible way for the synthesis of BL from biomass.

n-Butyl Pyridinium Nitrate as a Reusable Ionic Liquid Medium for Knoevenagel Condensation

The Knoevenagel condensation of carbonyl substrates with active methylene compounds proceeds smoothly with ammonium acetate as catalyst in n-butyl pyridinium nitrate to afford the desired products of good purity in moderate yields.

Cerebral and splenic infarctions after injection of N-butyl-2-cyanoacrylate in esophageal variceal bleeding

Variceal bleeding is the most serious complication of portal hypertension,and it accounts for approximately one fifth to one third of all deaths in liver cirrhosis patients.Currently,endoscopic treatment remains the predominant method for the prevention and treatment of variceal bleeding.Endoscopic treatments include band ligation and injection sclerotherapy.Injection sclerotherapy with N-butyl-2-cyanoacrylate has been successfully used to treat variceal bleeding.Although injection sclerotherapy with N-butyl-2-cyanoacrylate provides effective treatment for variceal bleeding,injection of N-butyl-2-cyanoacrylate is associated with a variety of complications,including systemic embolization.Herein,we report a case of cerebral and splenic infarctions after the injection of N-butyl-2-cyanoacrylate to treat esophageal variceal bleeding.

Di-(n-butyl)-phthalate-induced Oxidative Stress and Depression-like Behavior in Mice with or without Ovalbumin Immunization

Objective To investigate the relationship between atopic allergy and depression and the role of DBP in the development of depression. Methods BALB/c mice were randomly divided into eight groups：saline;ovalbumin （OVA）-immunized;saline＋DBP （0.45 mg/kg·183;d）; saline＋DBP （45 mg/kg·d）; DBP （0.45 mg/kg·d） OVA-immunized; DBP （45 mg/kg·d） OVA-immunized; saline＋hydrocortisone （30 mg/kg·d）; and hydrocortisone （30 mg/kg·d）-exposed OVA-immunized. Behavior （e.g. open-field, tail suspension, and forced swimming tests）, viscera coefficients （brain and spleen）, oxidative damage [e.g. reactive oxygen species （ROS）, malondialdehyde （MDA）, and glutathione （GSH）], as well as levels of IgE and IL-4, were then analyzed. Results In the saline and OVA groups, the degree of depression symptoms in mice increased with increasing DBP concentration. Additionally, the OVA-immunity groups were associated with more serious depressive behavior compared with the same exposure concentration in the saline group. Oxidative damage was associated with a dose-dependent increase in DBP in the different groups. IL-4 and IgE levels were associated with low-dose DBP stimulation, which changed to high-dose inhibition with increasing DBP exposure, possibly due to spleen injury seen at high DBP concentrations.Conclusion Development of an atopic allergy has the potential to increase the risk of depression in mice, and it seems that DBP helps OVA to exert its effect in our present model. Moreover, the results of our study implicate a certain connection between brain oxidative stress and depression, which deserves a further exploration.

Removal of a type of endocrine disruptors—di-n-butyl phthalate from water by ozonation

Ozonation of synthetic water containing a type of endocrine disruptor-di-n-butyl phthalate （DBP） was examined. Key impact factors such as pH, temperature, ionic strength, ozone dosage and initial DBP concentration were investigated. In addition, the activities of radicals on uncatalysed and catalysed ozonation were studied. The degradation intermediate products were followed and the kinetic of the ozonation were assessed as well. Results revealed that ozonation of DBP followed two mechanisms. Firstly, the reaction rate of direct ozonation was slower at lower pH, temperature, and ionic strength. Secondly, when these factors were increased for indirect radical reaction, higher percentage of DBP was removed with the increase of the initial ozone dosage and the decrease of the initial DBP concentration. In addition, tea-butanol, humic substances and Fe（Ⅱ） affected DBP ozonation through the radical pathway. It was determined that ozonation was restrained by adding tea-butanol for its radical inhibition effect. Furthermore, humic substances enhanced the reaction to some extent, but a slight negative effect would be encountered if the optimum dosage was exceeded. As a matter of fact, Mn（Ⅱ） affected the ozonation by ＂active sites＂ mechanism. In the experiment, three different kinds of intermediate products were produced during ozonation, but the amount of products for each one of them decreased as pH, temperature, ionic strength and initial ozone dosage increased. A kinetic equation of the reaction between ozone and DBP was obtained.

CuCl-catalyzed Oxidative N-Demethylation of Arylamines with tButyl Hydroperoxide

CuCl-catalyzed oxidative N-demethylation of arylamines proceeded in the presence of tert-butyl hydroperoxide. The one-electron transfer route of oxidative N-demethylation competed favorably with the H-atom abstraction route.

Modeling phase equilibria of semiclathrate hydrates of CH_4,CO_2 and N_2 in aqueous solution of tetra-n-butyl ammonium bromide

Semiclathrate hydrates of tetra-n-butyl ammonium bromide （TBAB） offer potential solution for gas storage, transportation, separation of flue gases and CO2 sequestration. Models for phase equilibria for these systems have not yet been developed in open literatures and thus require urgent attention. In this work, the first attempt has been made to model phase equilibria of semiclathrate hydrates of CH4, CO2 and N2 in aqueous solution of TBAB. A thermodynamic model for gas hydrate system as proposed by Chen and Guo has been extended for semiclathrate hydrates of gases in aqueous solution of TBAB. A correlation for the activity of water relating to the system temperature, concentration of TBAB in the system and the nature of guest gas molecule has been proposed. The model results have been validated against available experimental data on phase equilibria of semiclathrate hydrate systems of aqueous TBAB with different gases as guest molecule. The extended Chen and Guo＇s model is found to be suitable to explain the promotion effect of TBAB for the studied gaseous system such as, methane, carbon dioxide and nitrogen as a guest molecule. Additionally, a correlation for the increase in equilibrium formation temperature （hydrate promotion temperature, ATp） of semiclathrate hydrate system with respect to pure gas hydrate system has been developed and applied to semiclathrate hydrate of TBAB with several gases as guest molecules. The developed correlation is found to predict the promotion effect satisfactorily for the system studied.

Reactive dividing-wall column for the co-production of ethyl acetate and n-butyl acetate

Reactive dividing-wall column(RDWC) technology plays a critical role in the energy saving and high efficiency of chemical process.In this article, the process of co-producing ethyl acetate(EA) and n-butyl acetate(BA) with RDWC was studied.BA was not only the product, but also acted as entrainer to remove the water generated by the two esterification reactions.Experiments and simulations of the co-production process were carried out.It was found that the experimental results were in good agreement with the simulation results.Two kinds of RDWC structures(RDWC-FC and RDWC-RS) were proposed, and the co-production process operating parameters of the two types of RDWC were optimized by Aspen Plus respectively.The optimal operating parameters of the RDWC-FC were determined as follows: 0.6 of the reflux ratio of aqueous phase(RR), 0.66 of the vapor split(R_V) and 0.51 of the liquid split(R_L).And the optimal operating parameters of the RDWC-RS were shown as follows: RR was 0.295 and R_V was 0.61.Furthermore, the energy saving analysis of the co-production process was based on the annual output of 10000 tons of EA, compared with the traditional reaction distillation(RD) to prepare EA and BA, the reboiler duty of the RDWC-FC column could save 20.4%, TAC saving 23.6%; RDWC-RS reboiler energy consumption could save 17.0%, TAC 22.2%.

Extraction of Lithium from Brine Containing High Concentration of Magnesium by Tri-n-Butyl Phosphate Dissolved in Kerosene

Tri-n-butyl phosphate（TBP）dissolved in kerosene was chosen as extractant for lithium from a modelbrine having high magnesium-to-lithium ratio and ferric chloride was added to the system.The influences of con-tact time,concentration of the extractant,concentrations of some salts(Mg2+, Na+,K+)in the solution,acid-ity of hydrochloric acid and extraction temperature on the exttaction of lithium with TBP-kerosene system werestudied.The suitable extraction conditions were found to be:contact time not any less than 20min;at 20-25C;[Fe+3]/[Li+]about 1.5-2.0;TBP concentration 50%-70%;[MgCl2]exceeding 3 mol·L-1;pH about 2;while most sodium and potassium salts in the aqueous phase should be removed before the extraction.

Vapor Pressure, Vaporization Enthalpy, Standard Enthalpy of Formation and Standard Entropy of n-Butyl Carbamate

The vapor pressures of n-butyl carbamate were measured in the temperature range from 372.37 K to 479.27 K and fitted with Antoine equation. The compressibility factor of the vapor was calculated with the Virial equation and the second virial coefficient was determined by the Vetere model. Then the standard enthalpy of vaporization for n-butyl carbamate was estimated. The heat capacity was measured for the solid state(299.39–324.2 K) and liquid state(336.65–453.21 K) by means of adiabatic calorimeter. The standard enthalpy of formation ΔfH[crystal(cr),298.15 K] and standard entropy S(crystal,298.15 K) of the substance were calculated on the basis of the gas-phase standard enthalpy of formation ΔfH(g,298.15 K)and gas-phase standard entropy S(g,298.15 K), which were estimated by the Benson method. The results are acceptable, validated by a thermochemical cycle.

N-butyl-2-cyanoacrylate, iso-amyl-2-cyanoacrylate and hypertonic glucose with 72% chromated glycerin in gastric varices

cyanoacrylate and a mixture of 72% chromated glycerinwith hypertonic glucose solution in management ofgastric varices.METHODS： Ninety patients with gastric varicespresented to Endoscopy Unit of Ain Shams UniversityHospital were included. They were randomly allocatedinto three groups; each group included 30 patients treatedwith intravariceal sclerosant injections in biweeklysessions till complete obturation of gastric varices;Group I （n-butyl-2-cyanoacrylate; Histoacryl？）, GroupII （iso-amyl-2-cyanoacrylate; Amcrylate？） and GroupIII （mixture of 72% chromated glycerin; Scleremo？with glucose solution 25%）. All the procedures wereperformed electively without active bleeding. Recruitedpatients were followed up for 3 mo.RESULTS： 26% of Scleremo group had bleeding duringpuncture vs 3.3% in each of the other two groups withsignificant difference, （P 〈 0.05）. None of Scleremogroup had needle obstruction vs 13.3% in each of theother two groups with no significant difference, （P 〉0.05）. Rebleeding occurred in 13.3% of Histoacryl andAmcrylate groups vs 0% in Scleremo group with nosignificant difference. The in hospital mortality was 6.6%in both Histoacryl and Amcrylate groups, while it was0% in Scleremo group with no significant difference. Inthe first and second sessions, the amount of Scleremoneeded for obturation was significantly high, while the amount of Histoacryl was significantly low. Scleremo was the less costly of the two treatments. CONCLUSION： All used sclerosant substances showed efficacy and success in management of gastric varices with no significant differences except in total amount,cost and bleeding during puncture.

Synthesis and Crystal Structure of N-tert-butyl-N′-(2,4-dichlorobenzoyl)-N- [1-(4-chlorophenyl)-1, 4-dihydro-6-methylpyridazine-4-oxo-3-carbonyl] hydrazine

The title compound N-tert-butyl-N(-(2,4-dichlorobenzoyl)-N-[1-(4-chlorophenyl)- 1,4-dihydro-6-methylpyridazine-4-oxo-3-carbonyl]hydrazine [(C23H_21N4O3Cl3)2·1.5H_2O, Mr = 1042.60] was prepared by the reaction of 1-(4-chlorophenyl)-1,4-dihydro-4-oxo-6- methylpyridazine-3-carboxylic acid with chloroformate ethyl ester, then with N′-tert-butyl-N- (2,4-dichlorobenzoyl) hydrazine in the present of triethylamine. The crystal structure has been determined by X-ray diffraction. The crystal belongs to Monoclinic, space group P21/c, with unit cell constants a =11.4948(9), b=12.7495(10), c=35.854(3) ?, β =92.964(2)°, Z=4, V=5247.6(7) ?3, Dc = 1.320 Mg/m3, F(000) = 2156 , μ (MoKa)= 0.385, R = 0.0661, wR = 0.1875, for 9151 observed reflections( I >2σ(I)). The structure is a dimer linked by intermolecular hydrogen bond which can be observed between N(1)- H...O(6), N(5)- H...O(3). The distances are 2.068 and 2.027? respectively.